WO 00/39813 discloses a superconductor cable which comprises a tubular carrier on which a first layer of superconductive strips is wound.
The first layer is surrounded by a dielectric, on which a second layer of superconductive strips is wound.
The superconductive strips are located within a metallic layer.
In the case of this superconductor cable, the first layer serves as a phase conductor and the second layer as a return conductor. The phase conductor and the return conductor run coaxially in relation to each other.
On the second layer there is a further layer of copper strips, which serve as stabilization in the event that the cooling of the cable fails or a short-circuit occurs. The copper strips are in direct contact with the metallic layer in which the superconductor material is located.
A number of conductors constructed in this way are located in a cryostat, which insulates the superconductors from externally occurring heat.
The disadvantage of this conductor design is that the direct contact of the conductor of superconductive material with the conductor of normally conducting material and less than optimum stranding of the various layers cause losses to occur in the cable.